I Need Help With My Relationship!!!

This guy and I have been friends for over a year, three weeks ago he asked me out and we’ve been dating since. I thought I was emotionally prepared to date him and was ready, but I’ve been having doubts. I think I just want to be friends with him. Should I wait longer to tell him? Or should I tell him as soon as possible in person? I can tell he really likes me, but my heart isn’t personally in it romantically. I’m conflicted on what to do because I’m afraid if I tell him it will ruin our friendship. Any advice would be greatly appreciated!!